The End of the Tuolumne River! (It's not as bad as it sounds...)

The slough at the headquarters area of Dos Rios State Park

Back in the 1980s, Douglas Adams published his hilarious "trilogy" of the Hitchhiker's Guide to the Universe. The second book, The Restaurant at the End of the Universe, was not about a restaurant at the edge of the Universe, but rather it was a place where you dined and watched the actual destruction of the Universe (you had to use a time machine to get there). 

Today's blog is about the end of the Tuolumne River. But it isn't as bad as it sounds: it's about the spot where the Tuolumne River ends by flowing into the San Joaquin River. The confluence was on privately-owned ranch lands for many years, but a profound change is coming that will touch lives across our county and Central California. It is becoming California's newest State Park!

The confluence of the Tuolumne and San Joaquin Rivers

Dos Rios State Park is the product of years of cooperation between the owners of the Dos Rios Ranch, River Partners, and the Tuolumne River Trust. In the last decade or so, the partners worked to return the former croplands to a landscape that functions like the original primeval environment that existed before the invasion of industrial agriculture. In other words, a riot of canopy trees like oak and cottonwood with a tangled undergrowth of willows, elderberries and numerous other native plants. This floodplain woodland acts as a giant sponge, absorbing and slowing down floodwaters and helping to recharge the groundwater underneath.

The lower Tuolumne River near the confluence. The state park is on the right-side shore

The riparian environment provides a marvelous habitat for the wildlife that once thrived throughout the Great Valley of California (only about 5% of that original habitat remains). Dos Rios State Park will be a fantastic place to search for hundreds of bird species (more than 200 are known from just across the river at the San Joaquin River National Wildlife Refuge), and all manner of animal and plant species. The highly endangered Riparian Brush Rabbit is only found in an extremely small area within the San Joaquin Delta and the wildlife refuge across the river. I was told they intended to transplant a small group from the refuge to the park, but that the rabbits confounded the plan by crossing the river somehow and establishing a population all by themselves!

There are a number of ancient remnant environments tucked away in corners of the park. The most striking was a growth of valley oaks growing on a slightly elevated hill adjacent to the San Joaquin near the south end of the new park. There was a cacophony of bird songs in the canopy above, including Yellow-rumped Warblers, Oak Titmouse, White-crowned Sparrows, Tree Swallows, and Bush-tits.

The oak forest is a two mile walk from what will be the park headquarters area, and there are ideas of developing the site into an environmental walk-in campsite where local children can experience wilderness only a few miles outside their cities.

Much of the park will be a trailless, roadless morass of trees and brush on the floodplain. This is the area meant to serve for flooding relief, where it might remain underwater for weeks at a time. Volunteers have spent a decade planting native vegetation, and many of the trees are already tens of feet tall. They were irrigated for three years, but they will be able to survive on their own in the years to follow, watered by the higher groundwater table and occasional floods.

A "bunny hill" on the right side, a floodplain to the left.

Several elevated areas across the park provide refuge for mammals during flooding events. I believe they called them "bunny hills". I've seen these in action during floods across the river at the wildlife refuge, where everywhere I turned, rabbits were waiting for the floodwaters to subside.

The tangled thicket of native vegetation: the valley floodplain as it once was.

One of the most valuable aspects of the park is that it will allow visitors to experience the valley habitat as it once was, and how many parts can once again be. On our tour, we mentioned the wonderful resource of the Great Valley Museum at Modesto Junior College where I teach. Visiting the museum, children can view dioramas of the natural environments of the valley and even see a few live animals. But what if...they could learn about these environments, and then drive a short distance and actually experience them? That's the incredible value of the Dos Rios State Park.

Double-crested Cormorant in the slough

When our tour ended, I spent a few moments wandering the only developed part of the park. There is a picnic area that has been constructed adjacent to the farm buildings serving as the park headquarters for the moment. There is a slough below the picnic structures with a short walkway providing panoramic views. It didn't take long to find some interesting birds, like the Double-crested Cormorant drying its wings on a stump.

I only occasionally see Downy Woodpeckers along the Tuolumne upstream, but it was the first one I sighted today. I also saw Northern Flickers and Nuttall's Woodpeckers.

A Great Egret was watching for fish on the far side of the slough. 

Turtles were basking on logs down in the slough below.

Dos Rios State Park will open this coming summer with the picnic area and slough area open for visitation. A master plan will be developed over the next few years, with proposals for a campground, trails, and all manner of interpretive programs. Even better, the park will function as an environmental buffer, providing habitat and flood protection. The park is starting with about 2,100 acres, but other adjacent tracts are being "de-developed" to resemble their original habitat. 

It was a real privilege having the opportunity to see this park and renewed floodplain in the making. I'm looking forward to seeing what lies ahead for this beautiful new park in coming years. It is a marvelous resource for our community.

Source: River Partners and the Tuolumne River Trust

Hopes for the Healing of a River: Northern River Otters on the Tuolumne

I had the delightful privilege of watching a River Otter family hanging out along the Tuolumne River the other day. There were three of them, two adults and a juvenile. It's the most time I've ever seen any of them out of the water. It's a good sign that recovery is possible in a river system despite the abuses we've heaped on our wonderful gift of nature.

The Gold Rush of 1848 was catastrophic to the Tuolumne. Miners dug up river vegetation and processed literally all the river gravels for the elusive metal. Gold dredges did incalculable damage to stretches of the rivers in the Great Valley by ripping out the riparian vegetation and destroying the soils along the river floodplain. Underground mines brought minerals to the surface that oxidized to form acids and other toxins. Mercury used in the gold recovery process leaked into river waters. In the twentieth century we built massive dams that altered the water quality and flow levels. These have wreaked havoc with what remains of the natural ecosystem.

One of the bellwethers of the health of a river system is the presence or absence of apex predators and other native species. The predators cannot thrive if their prey species are not present, whether from pollution, drought or other cause. I'm always looking for signs that the native species are present and hopefully thriving. In the last few years I've run across bobcats, foxes, raccoons, beavers (gnawed trees, anyway), hawks and ospreys and Northern River Otters (Lontra canadensis). There was even a report recently of a Mountain Lion downstream in Modesto.

There used to be an even more diverse group of predators and prey species along this river. In historic times there were California Grizzly Bears, Black Bears, and Gray Wolves, along with the California Condor. In prehistoric times, the tally included Sabertooth cats, Dire Wolves, and several other rather scary beasts. The river was populated by gigantic tusked salmon up to nine feet in length.

Geologically, our river otters were a relatively late addition to the river ecosystems of North America. Their family evolved more than 30 million years ago, and spread throughout the Old World and migrated into the Americas, including the Giant Otter of South America. But the Northern River Otter fossil record only goes back to the beginning of the ice ages about 1.9 million years ago. They are related to European species, and probably came across the Bering Land Strait when sea levels were lower (although being an aquatic species, they could have swam the relatively short distance between Russia and Alaska).

The current range of the otter ends in our region. It's their frontier. According to the River Otter Ecology Project, there have been sightings on the Tuolumne River, and just one or two in the Merced River one drainage to the south (some otters were spotted in Yosemite Valley for the first time in decades recently). I'm hoping they will be able to spread farther south into the San Joaquin River drainage. I have seen them on the valley floor in the San Luis National Wildlife Refuge in a slough of the San Joaquin.

The otters cooperated long enough that I was able to get some video too. Enjoy!

At the Frontier: River Otters and the Tuolumne River

Here in California we've abused our rivers, especially in the Sierra Nevada, and in particular, the Tuolumne River, the one in my backyard. The Gold Rush of 1848 was catastrophic. Miners dug up river vegetation and processed literally all the river gravels for the elusive metal. Gold dredges did incalculable damage to stretches of the rivers in the Great Valley by ripping out the riparian vegetation and destroying the soils along the river floodplain. Underground mines brought minerals to the surface that oxidized to form acids and other toxins. Mercury used in the gold recovery process leaked into river waters. In the twentieth century we built massive dams that altered the water quality and flow levels.  There are recovery efforts happening, but it will be many more years before the river can be truly healthy for salmon and all the other life forms that historically lived along the river. There are many other challenges, like the invasive hyacinth, a water plant that clogs river channels, pollution, and low flows related to extensive droughts in California (the water is warmer than it should be).

One of the bellwethers of the health of a river system is the presence or absence of apex predators and other native species. The predators cannot thrive if their prey species are not present, whether from pollution, drought or other cause. That's always on my mind when I walk the shores of the Tuolumne River where it flows into the Central Valley. This stretch of river is controlled by a system of reservoirs and irrigation canals, and flows are tightly controlled most of the time. I'm always looking for signs that the native species are present and hopefully thriving. In the last few years I've run across foxes, raccoons, beavers (gnawed trees, anyway), hawks and ospreys and much to my delight on four occasions now, Northern River Otters (Lontra Canadensis). 

Source: http://www.sibr.com/mammals/M163.html

The current range of the otter ends in our region. It's their frontier. According to the River Otter Ecology Project, there have been sightings on the Tuolumne River, and just one or two in the Merced River one drainage to the south (some otters were spotted in Yosemite Valley for the first time in decades last year). 

The frontier once extended farther to the south. There's another river that has suffered even more degradation. It's the upper San Joaquin. It flows out of the Sierra Nevada high country between Yosemite and Kings Canyon National Parks. So much of the river has been diverted for irrigation that the river hasn't flowed on many stretches for more than half a century. There's no habitat for wildlife when there is no river. A series of lawsuits and agency agreements resulted in the formation of the San Joaquin River Restoration Project that recently saw water flow again in the river. Maybe there is hope that the river will host otters again as well.

My adventure with the otter this morning started when I was looking for birds along the river's edge. I happened to look down and saw a strange looking round head looking at me through the grass, It wasn't even a second, but I thought it might be an otter. I walked downriver a short distance and started watching. After about 10 minutes, the otter swam by me, maybe 25 feet away. I snapped two pictures, and then remembered the video. I hit the "play" button, and started contentedly watching the otter swim upstream at a languid pace. Then I hit the "play" button again and actually started recording (but not realizing it). In the end I got a one second video of otter, and a minute and a half of random swinging camera.

The top picture is the otter from this morning, the closest I've ever been to one. The second is a shot from much further away of an otter I saw three weeks ago. Since I didn't get the greatest video ever seen of an otter this morning, you'll have to settle for the video from three weeks ago. 

Liveblogging the Deluge: San Joaquin River National Wildlife Refuge - What a difference a few months made (and Rabbits)

The San Joaquin River at the National Wildlife Refuge in November 2017

Just a few months ago, the San Joaquin River, and its major tributary the Tuolumne River, were in big trouble. The worst drought in California's recorded history had left the rivers at a mere trickle, and many parts of the San Joaquin were dry, despite recent efforts to bring back some sort of minimal flows to stretches of river that had been dry for decades (after dam and irrigation levee construction upstream). The invasive weed River Hyacinth had choked channels, crowding out native vegetation and making life difficult for fish and other organisms.

I hiked the Pelican Nature Trail in the San Joaquin River National Wildlife Refuge back in November, and despite a few early storms, dryness was the overwhelming feeling. Volunteers have put in a vast amount of work replanting former riparian woodlands, but it felt like the river overflow areas wouldn't see water any time soon. The river was flowing at a sluggish couple of hundred cubic feet per second.

The San Joaquin River in the same exact location on February 14, 2017

I returned to the Pelican Trail yesterday to a changed world. A series of atmospheric river storms over the last six weeks have dumped record amounts of precipitation across northern and central California. Watermasters at the reservoirs upstream joyfully let their dams fill with the prodigious amounts of water, but then the storms kept coming and they realized that some of the dams were in danger of overflowing. They ramped up flows out of the reservoirs and the rivers downstream swelled. The Tuolumne River, for instance, has been flowing at near flood levels (~9,000 cubic feet per second) for the last five weeks, and this week the flows were increased to over 11,000 cubic feet per second. Don Pedro Dam is only 2-3 feet below full capacity, and has only about 30,000 acre-feet of capacity (out of 2.03 million acre feet of storage space). The Merced River has been experiencing high flows as well, and water is high in the usually dry San Joaquin riverbed. Yesterday the river at Vernalis, just downstream of my trail, reached official flood state at 34,000 cubic feet per second.

It was rather stunning to stand on one bank of the San Joaquin, the neglected trickle of water from the southern Great Valley, and not be able to discern exactly where, off in the distance, the other bank was located. And there is this: the water level is probably going to rise soon. Yet another intense storm is headed towards California, and there is going to be another week of rainfall and snow in the mountains upstream. Don Pedro Lake, for one, is just about full and it is possible they will have to let additional water through the system to keep the lake from overflowing.

More than a month ago, on January 4, I wrote the first of a series of blogs that I soon called Liveblogging the Deluge. I quite honestly thought it was going to consist of four, maybe five posts as the first atmospheric river storm passed through California. But another storm soon followed, and then another. I look back now and see that I've published 24 posts on the storms, and they keep coming. This has been an extraordinary storm event and, for some people, a scary experience. Nature cares little for human beings and our puny attempts to control it can sometimes result in failure and tragedy. Despite the evacuation of 180,000 people because of an unstable situation at Oroville Dam, we've kind of held things together in the north part of the state, but the system is presently strained to the limits. Levees are showing signs of failure in places and reservoirs are getting dangerously full. It is imperative that residents in California keep their eyes open, and when the warnings come and evacuations are ordered that they comply as quickly and orderly as possible. Making a principled stand to defend your house against a rising flood is dangerous and may be deadly.

By the way, the other strange sight on the Pelican Nature Trail was the prevalence of Desert Cottontail Rabbits. There were perhaps hundreds of them along the trail. I assumed they had been flooded out of their habitat on the flats below and had gathered on the high ground of the levee where they were nibbling at the smallest shoots of grass, or reaching for leaves on the lower branches of the shrubs.

They barely seemed to register my presence. I was stepping only two or three feet away from them before they would move into the brush along the trail. They only scattered rapidly once, when a Northern Harrier flew overhead. Human beings are not the only beings who are affected by the floods.

I'm not going to be able to liveblog the coming storm, as I will be out in the middle of it. We're headed out to the Death Valley region where we will be navigating between storms and flash floods. I expect to have some interesting observations once the storm is past and we are home again. And yes, we will be careful out there. It's not often that one gets to observe rain in the driest place in North America. See you in a few days!

Liveblogging the Deluge: A Tuolumne River Update, and Scenes on the San Joaquin

The travails at Oroville Dam are appropriately dominating the news this week as nearly two hundred thousand people remain isolated from their homes as the operators work to temporarily shore up the failing spillways at the lake. It should not be forgotten that most rivers in Northern California are running very high, and with yet another storm arriving this week, the threat of flooding elsewhere is still very real.

San Joaquin River near Stevinson

I don't have much information on the San Joaquin River, but I crossed the river yesterday near Stevinson on Highway 165, and it was well out of its banks. There are reports of flooding downstream west of Modesto. Although the river was clearly flooding, it was still well below the levees near the bridge I crossed.

San Joaquin River near Stevinson

I made it down to the Tuolumne River Parkway Trail this afternoon, and found that the river has reached the highest flows since the recent storm assault began in January. It is swollen with water released from Don Pedro Dam upstream.

The capacity of Don Pedro is 2.03 million acre-feet (water elevation 830 feet), and the latest measurements show the lake at just inches below 828 feet. Inflow has declined in the last day or so to 12,544 cubic feet per second, while outflow has been ramped up a bit past flood level, to 10,700 cubic feet per second, so the lake is still rising, albeit much more slowly than a few days ago. An announcement from Turlock Irrigation District indicates that they have no current plans to open the emergency floodgate.  If they do, it will be for only the second time ever. The first time was in 1997, and that event carved a new channel through a pasture area that reached a depth of 40 feet.

It's important in these days of evacuations in the Oroville Dam area to point out that there are big differences between the spillgates at the two dams. The floodgate at Don Pedro is more heavily reinforced and the former meadow slopes more gently, so undercutting of the gate is unlikely. The overflow channel, although not lined with concrete, passes no major infrastructure other than Bonds Flat Road, which washed out in 1997 (but was later repaired). If the storms fill the reservoir, the floodgates could indeed be opened, and some flooding would occur downstream, but not to the extent of the potential flood that threatens Oroville and other towns in the north valley.

Don Pedro Dam, courtesy of Google Earth

In the meantime, I am watching a powerful river changing things along my exercise trail. Portions of the trail were underwater, and the normally placid river is surging noisily downstream. High flows are expected to last for many weeks as the reservoir is prepared to accept the snowmelt that will begin soon. It has been a long time since things have been anything like this.

I'll repeat what I said in the last post. Flooding is a serious matter, one of the most dangerous of geological hazards. One thing that sets river floods apart is their predictability, in that rivers are closely monitored, and flood levels are almost always known with good accuracy hours and days ahead. This means that if you are told to evacuate, your life is in danger, and you should follow any directions and requests made by the authorities. Unlike the give and take of politics, there is no place for "unbelief" that the river will hurt you or your property. The river doesn't care what you believe. Just get out of the way.

The Sierra Beyond Yosemite: Another Caldera near Mammoth Lakes? Don't Worry About This One...

In the 1980s and unfortunate series of events led to conflict in Mammoth Lakes between geologists concerned about a possible volcanic eruption, and civic leaders and business people worried about their economy and profits. The conflict was exacerbated by irresponsible reporting in the national media. The problems would have been trivial had the volcano actually erupted, but in the end the magma cooled to solid rock at a depth of 7,000 feet or so.

Volcanic events of the last 8,000 years in the eastern Sierra Nevada, from interpretive display at the Mammoth Lakes National Forest Visitor Center

The possibility of volcanic activity in the Mammoth Lakes/Inyo Craters/Mono Lake area is very real. Studies show a dozen or more volcanic events in the last thousand years, and the region is constantly shaken by earthquakes, and riddled with hot springs and steam vents. Things have been mostly calm in recent years, and the warning stage is currently green. The Long Valley Caldera is currently at rest, but hot magma still exists at a depth of three or four miles.

As noted in some of my previous posts, the Long Valley Caldera exploded in apocalyptic fury about 760,000 years ago, releasing some 150 cubic miles of ash into the atmosphere. As the eruption evolved, the Earth's crust collapsed into a massive hole 20 miles long, 10 miles wide, and as much as three miles deep. Probably the last thing anyone would want to find out is that a second caldera exists in the region. But it's not anything to worry about. It went extinct around 100 million years ago in the middle Cretaceous period.

Try to imagine what it is like at a depth of two miles or so in the present day Long Valley Caldera. When the crust collapsed during the climactic eruption a hundred million years ago, huge chunks of rock hundreds, even thousands of feet across fell into the mix of magma and ash. And a great many dinosaurs perished (now that's a thought, but this was a much more local event, not the K/T extinction). A great deal of time passed. Plutons of molten rock intruded the old caldera, cooling slowly to form a granite-like rock, and metamorphosing the older volcanic rocks into slate, schist and greenstone. Even more time passed, and tectonic activity caused the crust to rise many thousands of feet. Erosion stripped away the overlying rock, and the depths of the ancient caldera were exposed to the air, water, and eventually, glacial ice. What had once been the deep interior of a gigantic caldera now stood as high castle-like cliffs. That is the story of the Minarets, seen in spectacular fashion from Minaret Summit just a few miles up the hill from the Mammoth Lakes ski resort.

The rugged ridge of the Minarets and the high peaks of Mt. Banner and Mt. Ritter are not actually on the eastern crest of the Sierra Nevada. They lie a bit to the west of Mammoth Mountain and the headwaters of the west-flowing San Joaquin River lie between the two ridges. The dark peaks of metamorphic rock have always contrasted strongly with the "usual" granite of the Sierra high country.

I once had a marvelous adventure in the Minarets. Decades ago, I was looking for a post-high school adventure, and ended up walking most of the John Muir trail. We tried to follow a few alternate routes in some places, including an attempt to make a cross-country climb over the pass above Iceberg Lake at the base of the Minarets. Unfortunately the lake was living up to its name, and was still frozen over. The pass above was covered in snow, and we had no equipment to surmount the obstacle. We had to backtrack quite a few miles to catch an alternate route. Just about then, our mosquito repellent ran out, so we more or less ran, arms waving at the swarming insects, ten miles or so to Reds Meadow and Devils Postpile. The Minarets had totally rebuffed our efforts to pass through. We took an alternate route that involved hitchhiking to Mammoth Lakes, consuming hamburgers, and following a much easier trail past Duck and Purple Lakes.

I've wondered why the Minarets were never incorporated into nearby Yosemite National Park. I strongly suspect that the metamorphic rocks had mineral plays and potential mining claims. I've heard (but can't confirm) that a large body of magnetite somewhere in the Minarets screws up attempts at orienteering with compasses. In any case it's a protected wilderness today, and a spectacular place to view some of the more unusual rocks to be seen in the high country of the Sierra Nevada. And there aren't any active magma chambers underneath.

Traveling in the Way-Back Machine: The Great Valley as it once was...

Sometimes the interesting revelations just happen. I haven't kept up with the America's Never Never because I was out of town doing something really strange: relaxing. As you might guess from the previous post, we spent a couple of days on the Big Sur coastline simply reveling in the cool air and enjoying a couple of beaches we had never visited before (more on them in later posts). The big surprise happened as we were leaving town: we got caught in a time machine and were transported a few hundred years into the past.

California's Great Valley is one of the most important agricultural regions on the planet. I've lamented a few times on the dreariness of living in the dust, the chemical pesticides, the fertilizers, and the horrible economic conditions (we still have poverty and unemployment at perhaps twice the national rate). But most of all I lament at how much we have changed the landscape, and co-opted the native environment and bent it to our own needs and desires. The California Prairie-lands barely exist anymore. When I've written on them in the past, I've explored the edges, the Sierra Nevada foothills where the soils are poor and therefore undeveloped except as grazing lands. In the interior parts of the valley, though, little of the original landscape remains, less than 5%.

 On our way to the coast, we discovered that it isn't all gone yet. Our route, Highway 165 south of Turlock, took us through the San Luis National Wildlife Refuge. The preserve covers 26,000 acres of San Joaquin River wetlands, grasslands, and vernal pools. We've always been in a hurry before, but not on Sunday. We saw a sign for an auto-tour route through part of the refuge, and we pulled off.

It truly was taking a time machine into the pre-European invasion of the Great Valley. The scene was peaceful, where the cacophony of bird calls almost drowned out the distant noise of highway traffic. One could look past the grasslands to the distant Coast Ranges and get a feel, if only for a moment, of how the valley once was. We actually stopped at the refuge twice, at mid-day on Sunday, and at sunset on Tuesday.

It would not be correct to say that we were standing in the middle of a pristine wilderness. Much of the land we were exploring was probably used for grazing and planting in the past. Many of the grasses are no doubt invasive species. And the water flows are managed. The administration of the wildlife refuge is attempting to maintain the wetlands and increase their area to reclaim a portion of the vast migratory flyway of California that has been co-opted in so many other parts of California. They are trying to restore some semblance of balance to the local ecosystem, because it has influences that stretch for thousands of miles from Central America to the Arctic. Untold millions of birds (and numerous other species in the ecosystem) are affected by our choices.

The heart of restoring this landscape is the San Joaquin River. For decades, long stretches of the river on the floor of the Great Valley were dry because of upstream diversions for irrigation. The last few years have seen a restoration of minimum flows of the river through the refuge, in part to reclaim wetland environments, and an effort to restore salmon habitat. It was good to see a river at work again for something besides an agricultural baron.

We'll be back. There are several other auto tours, including one that offers possible views of a tule elk herd, and a number of hiking trails. It's always a pleasure making new discoveries in one's back yard!

The Airliner Chronicles: Three Faces of California's Great Valley

According to this interesting article from the New York Times, it's larger than 9 American states. It is the largest patch of Class 1 Soil in the world (i.e., the best for agriculture). More than 230 kinds of crops and produce are grown there, and the output represents 8% of the nation's agricultural output (on 1% of the land). Around 6.8 million people live there, and the average per capita income is lower than most of the rest of the country (it has three of the five poorest cities), and unemployment is far higher. It is California's Great Valley, my home.

From http://en.wikipedia.org/wiki/File:Map_california_central_valley.jpg

The valley is 400 miles long, 30-50 miles wide, and is almost entirely flat (except for the Sutter Buttes, the highest elevations are 400 feet or less). It is drained by several major rivers, including the Feather and Sacramento Rivers to the north, and the San Joaquin, Kings and Kern Rivers to the south. Although most of the rivers leave the valley through the Sacramento Delta into San Francisco Bay, those in the south do not. They once ended in huge lakes like Tulare and Buena Vista, but today the lakes are long gone, having been dried up by agricultural diversions upstream.

I've long heard that only 5% of the valley remains in the natural state that existed prior to agricultural development, and from the air, this is obvious. All the times I've flown over it, I have been struck by the continuous patchwork of plowed fields (it clearly resembles the kinds of blankets my grandmother used to make out of the leftover fabric squares). There are a few tracts of undeveloped grasslands off to the south, but for the most part only the rivers retain much of their original vegetation, but only in a few places.

Today's photos come from three distinctly different parts of the valley's river systems. In the colorful top photo, we can see a portion of the Sacramento Delta, where the San Joaquin and Sacramento Rivers come together in a maze of islands that have been mostly converted to farmlands. The islands are protected (somewhat) from seasonal floods by a series of poorly constructed levees that are subject to destruction from even moderate earthquakes. This has set up what potentially could end up as California's worst possible natural disaster (at least in the monetary sense). The islands have been sinking due to groundwater withdrawal, soil loss, and oxidation of organic material in the soils. Most of them are now below sea level, with only the vulnerable levees keeping them from being flooded. Since the intake pumps for the California Water Project lie in the midst of these islands, broken levees will draw salt water into the delta, where the domestic water supply for most of the southern state is tapped. An earthquake has the capability to disrupt the state water system for several years.

The north end of the Great Valley is drained by the Sacramento River which can be seen in the photo above, taken near Colusa. The landscape has been completely co-opted by agricultural fields, right up to river's edge. It looks like the river has been "conquered" and tamed by the works of humankind, but floods like those of 1997 and especially of 1861-62 could leave just about the entire area in the photo above under 10-20 feet of water (see my take on these ARkstorms here).

The San Joaquin River drainage contains some of last remaining natural grasslands and riparian landscapes in the Great Valley. The structure of the valley is that of a series of shallow basins separated by the alluvial fan systems formed by the Merced and San Joaquin Rivers. The basins have essentially caused the river to back up and develop wide floodplains where the streams meandered widely, changing channels in unpredictable ways. The area in the picture above is just north of the town of Los Banos, an area of abandoned meanders, bogs and swamps protected as the San Luis National Wildlife Refuge and Great Valley Grasslands State Park. The land is not entirely unaffected...decreased flows caused by reservoirs and diversions upstream have caused many of the swampy areas to dry up. Efforts (and negotiations) are ongoing to increase river flows in a hope of rebuilding the disrupted ecosystems, especially those of the salmon which used to be common in these waters.

The Airliner Chronicles is one of my on-again/off-again serial features, which is usually updated whenever I fly somewhere.